[Fizz] Do not allow abort reentrancy (#36574)

Aborting is a gate you can only pass through once. A request that is
already aborting, already completed, or already fataled cannot be
aborted a second time. Previously this was generally functionally true
but you could contrive sequences where an onError would fire after a
render fataled. This change makes it more explicit that this is not
semantically correct by bailing out of abort if the request is in a
status that cannot be aborted.